Glossary · Billing
No-fault / auto insurance
No-fault/auto insurance pays for medical care arising from a vehicle accident regardless of who caused the crash. It is a primary payer under Medicare's coordination-of-benefits rules and must be billed before Medicare or most other health plans.
Verified May 8, 2026 · 5 sources ↓
Definition
Source · Editorial summary grounded in 5 cited references ↓
No-fault insurance—most commonly encountered as the Personal Injury Protection (PIP) or Medical Payments (MedPay) component of an automobile policy—covers health care costs resulting from a motor-vehicle accident without requiring a determination of fault. Per CMS coordination-of-benefits policy, no-fault insurance is classified as a primary payer; Medicare and commercial group health plans become secondary and cannot be billed first simply because the auto carrier is slower or more burdensome to work with.
For orthopedic practices, auto/no-fault cases arise most often after trauma: fractures, dislocations, cervical or lumbar spine injuries, and soft-tissue injuries to the shoulder or knee. Each state governs its own no-fault laws, meaning benefit limits, allowable fee schedules, required claim forms, and filing deadlines vary widely. Some states use a verbal or monetary threshold before tort liability attaches; others are pure no-fault. Practices must verify the applicable state rules, the policy's coverage limits, and whether those limits have been exhausted before routing charges to a secondary payer.
Claim submission for no-fault typically requires the CMS-1500 (or its electronic equivalent, the 837P transaction) along with accident-specific documentation: date and description of the accident, the insurer's claim number, and—critically—external-cause ICD-10-CM codes (V and Y chapter codes) that link the diagnosis to the accident mechanism. Many auto carriers also require their own proprietary claim forms or authorization numbers, and some mandate independent medical examinations (IMEs) before authorizing surgical procedures. Failing to follow these carrier-specific requirements is the leading cause of no-fault claim denial in orthopedic billing.
Why it matters
Billing a group health plan or Medicare before exhausting no-fault benefits constitutes an improper primary-payer arrangement and can trigger Medicare Secondary Payer (MSP) recovery demands, overpayment notices, and potential False Claims Act exposure. Conversely, failing to bill no-fault at all—or letting the policy's filing deadline lapse—leaves recoverable revenue on the table and may force the practice to write off charges that were legitimately covered. Because no-fault fee schedules are often separate from Medicare or state Medicaid fee schedules, reimbursement rates can differ substantially, making correct payer sequencing a direct revenue variable, not just a compliance checkbox.
Common mistakes
Where people most often go wrong with this concept.
Source · Editorial brief grounded in cited references ↓
- Billing the patient's group health or Medicare plan first because the auto carrier has a longer adjudication timeline—this violates MSP coordination rules.
- Omitting external-cause ICD-10-CM codes (e.g., V49.9XXA for an unspecified car-occupant injury, initial encounter) from the claim, causing the auto carrier to deny for lack of accident linkage.
- Missing the no-fault carrier's filing deadline (which can be as short as 30 days in some states) and then being unable to bill any secondary payer because the primary was not properly exhausted.
- Assuming the no-fault benefit limit is unlimited—most PIP policies cap at $10,000–$50,000, and charges beyond that limit must be routed to the correct secondary payer promptly.
- Using a standard health-plan authorization number instead of the auto carrier's claim number in Box 23 of the CMS-1500, causing misrouted or denied claims.
- Failing to append the correct 7th-character extension (A = initial encounter, D = subsequent encounter, S = sequela) to injury ICD-10-CM codes, which auto carriers scrutinize to determine whether care is still acute and accident-related.
- Not obtaining the patient's signed assignment-of-benefits or medical-authorization form specific to the auto carrier before submitting claims, leading to payment sent directly to the patient rather than the practice.
Related codes
Codes commonly involved when this concept appears in practice.
CPT
- 99213 $95.19Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.
- 99214 $135.61Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.
- 99215 $192.39Highest-level office or outpatient E/M visit for an established patient, qualifying via high-complexity medical decision making or 40–54 minutes of total provider time on the date of service.
- 27447 $1,159.35Knee replacement surgery addressing both the medial and lateral tibiofemoral compartments, with or without resurfacing of the patella.
- 27130 $1,162.02Primary total hip arthroplasty replacing both the acetabular socket and proximal femoral components with prosthetic implants, with or without bone graft.
- 29881 $515.71Knee arthroscopy with surgical removal of the medial or lateral meniscus, including any associated cartilage shaving or debridement performed in the same or a separate compartment.
- 29827 $976.31Arthroscopic surgical repair of the rotator cuff, performed entirely through the shoulder joint via endoscopic technique.
- 22633 $1,700.11Single-level lumbar arthrodesis combining posterior or posterolateral technique with posterior interbody technique, including laminectomy and/or discectomy sufficient to prepare the interspace — performed as one surgical session at one lumbar interspace.
Modifiers
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01Is no-fault insurance always the primary payer over Medicare?
02What ICD-10-CM codes are required on a no-fault auto claim?
03Can I bill the patient out-of-pocket while the auto claim is pending?
04What happens when the PIP benefit limit is exhausted?
05Do auto carriers follow the same fee schedules as Medicare?
06Is an independent medical examination (IME) common in auto injury cases?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01cms.govhttps://www.cms.gov/medicare/coordination-benefits-recovery/beneficiary-services/liability-no-fault-workers-compensation-reporting
- 02cms.govhttps://www.cms.gov/files/document/fy-2025-icd-10-cm-coding-guidelines.pdf
- 03apta.orghttps://www.apta.org/your-practice/payment/coding-billing/icd-10/faqs
- 04aaos.orghttps://www.aaos.org/quality/coding-and-reimbursement/
- 05CMS Medicare Secondary Payer (MSP) statute, 42 U.S.C. § 1395y(b)
Mira AI Scribe
When Mira detects that the encounter reason is linked to a motor-vehicle accident, it will (1) prompt the provider to confirm accident date, state of occurrence, and at-fault status so the correct payer sequence can be established before claim generation; (2) auto-suggest the appropriate V-chapter external-cause ICD-10-CM code (e.g., V49.9XXA for initial encounter) alongside the injury diagnosis code, ensuring the claim carries the accident linkage the auto carrier requires; (3) flag the 7th-character extension based on encounter context—'A' for the first visit, 'D' for follow-up, 'S' for sequela—reducing the single most common denial reason in auto claims; (4) surface a payer-sequencing alert if the patient also carries Medicare or a group health plan, reminding the biller that no-fault is primary under MSP rules; and (5) note any state-specific PIP filing deadline in the billing queue so the team can prioritize submission. Mira will not generate a no-fault claim without confirming that a carrier claim number and accident date are present in the record, since missing either field triggers near-universal auto-carrier rejection.
See Mira's approachRelated terms
Coordination of benefits (COB) is the process by which two or more health insurance plans divide payment responsibility for a single claim, establishing which plan pays first (primary) and which pays second (secondary) so that combined payments never exceed 100% of the allowed charges.
Workers' compensation (WC) is a state-regulated insurance system that covers medical treatment and lost wages for employees injured on the job. For orthopedic billing, WC claims operate under separate fee schedules, documentation requirements, and coding rules that differ substantially from commercial insurance and Medicare.